1. Field of the Invention
The present invention relates to air conditioning, and more particularly, to a dehumidification apparatus for removing moisture from the air and lowering a temperature of the air, and an air conditioning apparatus and system having the same.
2. Description of the Background Art
Air conditioning is to keep temperature, humidity, air stream, bacteria, dust and harmful gas in the best conditions for persons or objects indoors. The representative air conditioning functions include cooling and heating relating to temperature control, and dehumidification and humidification relating to humidity control.
In addition to electricity generation, the cogeneration supplies heat to district heating or industrial processing by using the waste heat from the electricity generation process.
FIG. 1 is a concept view illustrating a heating process of houses by cogeneration.
Waste heat discarded from the process of electricity generation of a cogeneration plant 10 is stored in a thermal storage tank 11, and transferred to a liquid (water) flowing in a heat transfer line 14 through a heat exchanger 12 by a circulation pump 13. The resulting hot water is transferred to a cooling/heating system 20 of the houses.
A heat exchanger 21 of the cooling/heating system 20 exchanges heat between the hot water and the water circulating in a hot water circuit 22. Then, the hot water is supplied to the houses in response to demand in the houses.
Since the production ratio of power to heat is fixed to about 3:4, it is advantageous if the ratio of demands for power and heat is close to the production ratio. However, the demands for power and heat from commercial or residential sectors show very different patterns from each other in annual variation.
The demand for power has a maximum value in summer with a relatively small annual fluctuation, while the demand for heat has a large fluctuation with a maximum value in winter. According to a statistical review, the ratio of the minimum to the maximum in the annual heat demand is only 8.7% in middle and high latitude regions.
FIG. 2 is an instance showing monthly heat/electricity supply from a district heating corporation.
As shown in FIG. 2, according to the demand for heat, the heat supply N2 from the district heating corporation has a minimum value from June to September, namely, a hot season. A particular point in the graph is that the electricity supply N1 becomes almost zero in the summer regardless of the increasing demand in the electricity in the summer. This is because the cogeneration stops in the summer and the small heat demand is sufficed by a dedicated boiler for heat supply. The reason for this is that the operation of the cogeneration is economically efficient and energy efficient as well only when the demand ratio between electricity and heat matches well with the production ratio, as mentioned previously. When the demand ratio deviates much from the production ratio, the operation of cogeneration becomes economically inefficient and the cogeneration process needs to be stopped.
As described above, the efficient operation of the cogeneration plant cannot be ensured in summer without increasing the demand for the waste heat generated as a byproduct from the electricity generation.
As shown in FIG. 1, in order to increase the demand for heat in summer, the district cooling has been devised applying an absorption type chiller 23 using the district heat as the heat source. However, the absorption type chiller 23 has a drawback in that the cooling performance of the chiller decreases considerably with a low temperature heat source such as the waste heat from the cogeneration plant 10. In addition, the cold water circuit 24 connected to the absorption type chiller 23 must be installed separately from the hot water circuit 22.